The prescription on the prescription glasses and the clear glasses makes the difference. The lenses for nearsighted people are thinner in the middle and thicker all around. But the lenses for farsighted people are thick in the middle and thinner all around. Some lenses for people who are slightly farsighted seemed to be alomst the same with non-prescription lenses.
Different people may have different ideas. To the nearsightes people, the difference between prescription glasses and clear glasses may be noticeable.While young people with slightly farsightedness will find there's little difference between the prescription glasses and clear glsses.